Opals are highly sought after gemstones. These unique stones do not have an official valuation system like other precious gemstones do. This makes determining the value of an opal much harder when you’re shopping for one. There are known characteristics that contribute to their value, with the most important ones being color, pattern and clarity. By familiarizing yourself with the different types of opals and their features, you can make an informed decision when you make your purchase.

Steps

Method1

Expanding Your Opal Knowledge

1

Familiarize yourself with opals and their terminology. Opals differ from other precious gemstones in their basic composition and how they are valued. These unique stones come in a wide range of colors and patterns, both of which can change, depending on the angle you view them from. Since buying an opal can be a significant investment, learn as much as you can about them before you start shopping. This will ensure you make an informed decision and get what you pay for.

Research reputable websites, favoring informational ones over retailer websites. Look into books on the subject. Get familiar with opal-specific terminology.[1]

Identify the types of natural opals available.[2] Natural opals, as opposed to man-made and synthetic opals, are the most expensive and precious stones you can buy. There are four main types – boulder (also known as matrix) opals, black opals, white opals and crystal opals. They differ from each other greatly in appearance.

Black opals are the most rare and expensive of all. They aren’t actually black (they come in a range of brilliant colors) but instead have a dark body tone. The demand for these opals is high.

Boulder (also known as matrix) opals have a dark body tone that looks similar to the black opal. They cost less, but come in a similar range of brilliant colors.

Crystal opals are unique because they’re transparent to semi-transparent in appearance. They can have a very glassy surface and dark or light body tones. The color often determines their value.

White opals have a milky body tone. They are much more common than black opals and don’t feature the same brilliant hues. While less expensive than black opals, white opals can be very beautiful and colorful when of high quality.[3]

3

Distinguish natural opals from modified and man-made versions.[4] Modified opals are referred to as doublets and triplets. A doublet isn’t a full opal, but instead, a thin slice of opal (usually crystal or white) glued onto a backing of plastic or black glass. Triplets are the same as doublets, except they feature an additional layer of clear plastic or glass over the opal.[5] Synthetic opals have the same composition and physical structure as natural ones, but they are made in a lab. Because they’re man-made, synthetics appear glassier and the color schemes and patterns are a lot more regular and organized.[6]

Doublets, triplets and synthetics are all worth much less than natural opals.

If you inspect the sides of doublets and triplets, you can spot their layers. This makes them easily recognizable.

4

Recognize how opal stones are valued. Opals don’t have an official valuation process like other precious gemstones. This can make it difficult to know exactly what you’re getting and a lot of the value is subjective in nature. However, there are some key characteristics you can use to assess an opal’s value. The most important factors are the range of play of colors, patterns, opal class, body tone, brilliance, thickness, color bar and faults.

“Play of color” means the range and brilliance of the hues visible in an opal when viewed from different angles.

The most valuable type of opal will have a play of color that covers its entire surface and can be seen from multiple angles.[7]

Method2

Evaluating Opal Stones

1

Pinpoint your price range and how you plan to use the opal.[8] You will set out knowing what you’re looking for and be more focused when evaluating the stones if you consider this information first. Set a price range for yourself and stay within it. Opals can be purchased to be set as rings, pendants, earrings and bracelets. The size of your opal will be determined by how you want to wear it.

For example, if you are buying opals to set as earrings, you will be choosing smaller stones than what you’d choose for a pendant or bracelet.

If you are shopping for a highly valuable opal, you’ll want the setting to also be of high quality.[9]

2

Inspect the color and pattern of the stone.[10] Color is a major factor when assessing the value of an opal. The range of colors exhibited when viewed from different angles (known as the play of color) is one aspect of this. Highly valuable opals will feature a range of brilliant hues that change and flash, depending on your perspective. The more play, the higher the price. The pattern of color is another factor. An opal without a full play of color can still have striking and unique patterns that increase their value. Patterns to look for are color ribbons, harlequin, rainbows and other variations.

The rarest visible color in opals is red, making it the most pricey, followed by orange, yellow, green, and blue. Blue is the most common visible color in opals.[11]

The most common pattern is the “floral” pattern, which can be described as colors that are randomly spread throughout the face of the stone.[12]

3

Assess the clarity and transparency.[13] Aside from color and pattern, clarity is the other major factor that determines an opal’s value.[14] Clarity is the degree of transparence the stone displays. Opals can range from transparent to opaque. The value of the clarity level depends on what kind of opal it is. A crystal opal of high value will feature extreme clarity and transparency. On the other hand, black opals are considered more valuable if they are opaque.

Clarity can also be disrupted by flaws like fractures, surface blemishes, cracks and pits. All of these will decrease the value of an opal.

Method3

Selecting and Purchasing Your Opal

1

Choose a good retailer.[16] Opals are expensive, so it’s important to shop with a jeweler you can trust. Start by dropping into the jewelry retailers in your area. Assess each one’s display – is it neat and orderly? Are the items well-maintained, or do they have dust on them? How wide is the collection and how maintained is the shop in general? Make your decision based on what you find out. Avoid the larger chain jewelry shops that advertise loudly about their discounts. The quality of their stock is generally low in comparison to other shops.

Use caution if you plan to purchase online. Digital images can distort the look of the stones and you can’t hold them in your hands and inspect them closely. Opals are expensive and it’s hard to spend that amount of money without seeing something in person.

2

Compare it with several other opals before making a final decision.[17] Once you’ve settled on the opal you want, take the time to closely compare it to two or three other opals in the shop. Hold them side by side and note the similarities and differences in color, pattern and clarity. Make sure the opal you buy is absolutely the one you want.

3

Inspect the stone closely under sunlight before you buy it.[18] Put your opal under scrutiny one last time. Turn it over – does it have backing? If so, it’s not a full opal and you need inquire about it. Inspect the opal from both sides to confirm whether it’s natural or man-made – look for layers of other materials. If you want to buy a full opal, it should be 100% opal with no other materials.

Lastly, ask to inspect it under sunlight. This will give you a better view into the stone’s clarity and may reveal flaws that you missed.

4

Obtain a signed Certificate of Authenticity from the retailer.[19] Always request and obtain a certificate of authenticity when you buy an opal. Make sure that it is signed. You’ll need this certificate for insurance purposes and resale value in the future. A certificate also holds the dealer accountable for what you’ve been sold, which is helpful if you end up having problems with the stone.